diff --git a/lib/mongolly/extensions/mongo/mongo_client.rb b/lib/mongolly/extensions/mongo/mongo_client.rb
index 35d2c2b..96ca68c 100644
--- a/lib/mongolly/extensions/mongo/mongo_client.rb
+++ b/lib/mongolly/extensions/mongo/mongo_client.rb
@@ -60,6 +60,7 @@ def backup_instance(address, options, lock = true)
           snapshot = volume.create_snapshot("#{options[:backup_key]} #{Time.now} mongolly #{host}")
           snapshot.add_tag('created_at', value: Time.now)
           snapshot.add_tag('backup_key', value: options[:backup_key])
+          snapshot.add_tag(options[:custom_tag_key], value: options[:custom_tag_value] || 1) if options[:custom_tag_key]
         end
       end
     end
diff --git a/lib/mongolly/shepherd.rb b/lib/mongolly/shepherd.rb
index 109849a..a728913 100644
--- a/lib/mongolly/shepherd.rb
+++ b/lib/mongolly/shepherd.rb
@@ -37,9 +37,11 @@ def cleanup(age)
       @logger.debug "deleting snapshots older than #{age}}"
       ec2.snapshots.with_owner(:self).each do |snapshot|
         unless snapshot.tags[:created_at].nil? || snapshot.tags[:backup_key].nil?
-          if Time.parse(snapshot.tags[:created_at]) < age
-            @logger.debug "deleting snapshot #{snapshot.id} tagged #{snapshot.tags[:backup_key]} created at #{snapshot.tags[:created_at]}, earlier than #{age}"
-            snapshot.delete  unless @dry_run
+          if @options[:custom_tag_key].nil? || @options[:custom_tag_key] && snapshot.tags[@options[:custom_tag_key]] == (@options[:custom_tag_value] || 1)
+            if Time.parse(snapshot.tags[:created_at]) < age
+              @logger.debug "deleting snapshot #{snapshot.id} tagged #{snapshot.tags[:backup_key]} created at #{snapshot.tags[:created_at]}, earlier than #{age}"
+              snapshot.delete  unless @dry_run
+            end
           end
         end
       end